It is a triumph of logistics, preparation and commitment that has happened each year since 1976, spanning the careers of two heads, three deputies, hundreds of staff and thousands of parents and children associated with the school in Bedworth, Warwickshire.
This year, the production, performed on two evenings to a total audience of 1,400 family members and friends is inspired by the juxtaposition of the World Cup finals and the Queen's 80th birthday. It is called "The Best of British" and the script and overall production is by the current head Rod Steward. (Queen and Duke are present, of course, as puppets in the Royal Box, their scripts read out of sight. At one point Her Majesty is told off by her Consort for fretting too obviously about missing a crucial moment in Big Brother - "How long does this go on?") Mr Steward is in no doubt of the value of the enterprise. "Like every primary head, I have lots of visits from former pupils and not one of them has ever said to me, 'That was a marvellous maths lesson I had that day'.
It's usually about anything to do with performance - those are the best memories of their school life."
These memories now extend well into adult life. Canon Maggs has become synonymous in the town with its productions, which are there in the mix when choices of school are being made. Mr Steward has now been working on these productions - and others - for 20 years as deputy and head, and so I got him to share some of his secrets with us.
* Canon Maggs productions work because there is a long-standing relationship with the nearby Civic Hall and its staff, and a history of give and take and mutual understanding of problems.
* The production is now an established part of the school year. New members of staff and incoming Year 3s are absorbed quickly into the culture.
* With care in the writing, many of the year's events are incorporated - this year some work on Shakespeare has become a feature of the Year 6 contribution.
* It does not dominate the term. Mr Steward works on the structure and the script after half term and production properly starts after Sats - never more than three weeks before opening night.
* The structure is held together by a simple script, and the set pieces are delegated to year groups. Each contribution is based round one or more popular songs that the audience will enjoy and which are easy to learn and choreograph.
* Though it is mostly a fun event, there are well-placed "reflective"
moments - in this case a reference to global issues, and a Remembrance Day sequence.
* Children with out-of-school accomplishments (music, dancing) have a chance to show them.
* All the children are in the hall all the time - either on stage or on the front seats waiting. There's no need to have masses of excited children and frazzled staff waiting backstage.
* Music and action are better than words. In a big hall a wordy script just doesn't work.
* The show's always up-to-the-minute. Three days before this year's opening, many final details were waiting for the insertion of World Cup references.